Periodontal disease is a kind of the chronic disease, occurs at a high frequency throughout the world. According to the statistics of Taiwan Academy of Periodontology, over 90 percents of adults have gum disease in Taiwan. These patients might have ugly teeth, bad breath and suffer from other oral diseases. Moreover, it seriously affects the interpersonal relationships with others during social activities. The main factor of periodontal disease is the growth of the oral pathogens, others include smoking, genetic, stress, diet, age, diabetes, osteoporosis, HIV infection, radiation exposure and administration of drugs that suppress the immune ability and so on. These factors are likely to increase the risk of suffering from periodontal disease and also exacerbate the damages done by those pathogens.
In between gums and teeth is a groove and the groove is called the gingival sulcus. Result of poor oral hygiene, the oral pathogens would grow in the gingival sulcus and gradually to form a biofilm. These main oral pathogens are Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans. These oral pathogens adhere and aggregate to the biofilm to form a plaque.
The oral pathogens within the plaque will invade the surrounding gum tissue, and gradually form a periodontal pocket. The invaded oral pathogens itself and its secreted toxins will induce the pro-inflammatory factors, including cyclooxygenase (COX) products and inducible NO synthase (iNOS) metabolites, etc. These factors will directly or indirectly cause damage to the surrounding gum tissue.
In clinical practice, it is very important to observe the height of periodontal alveolar bone in patients. Because the height of the alveolar bone will directly affect the holding of the teeth. The density of bone within our body is the result of constant interaction between deposition and resorption. When the rate of the deposition is faster than the rate of resorption, the internal bone is increased. If the rate of the resorption is faster than the rate of deposition, the internal bone is decreased. Periodontal alveolar bone works the same mechanism. The deposition and the resorption of bone depends on the osteoblasts and the osteoclast. When the pathogens enter the alveolar bone, the pathogens will destroy the capillary blood vessels, block the supply of the nutrients and reduce the osteoblast activity. On the other hand, the inflammatory factors (e.g., TNF-α, IL-1) and immune cells (e.g. T cells) induced by the pathogens, increase the osteoclasts activity tremendously. These situations cause alveolar bone atrophy and bone loss, further leads to exposure of teeth root and loss of teeth
In summary, the pathogens in the plaque is the main reason of the periodontal disease. Thus reducing the accumulation and proliferation of these pathogens are the primary goal of prevention and treatment of periodontal disease. In clinical, the main cure method of the periodontal disease is through surgical treatment to clear of the plaque. Currently, there is no efficienct drug therapy for the periodontal disease. Therefore the drug therapy is a very important field for further research and development.